Sizing conduit for long pull - Electrician Talk - Professional Electrical Contractors Forum

bharbwyr · 11-11-2009, 06:40 AM

I'm gearing up to pull almost 500' of 250kcmil aluminum through pvc conduit. Other than the steel sweeps at both ends the path is pretty straight, dipping down in the middle and gently sweeping across the driveway to the house. Can anybody out there recommend, based on their experience, the minimum conduit diameter that should keep me out of trouble? I'm hoping to be able to do it with manpower alone, maybe 3 or 4 guys. Is that ridiculous?
The cable will be 250,250,3/0 URD,USE and a #2 XHHW EGC

480sparky · 11-11-2009, 08:53 AM

The legth of a run makes no difference as far as the NEC is concerned. As long as raceway requirements are met, that's all you need.

If it's a going concern for you, up it one trade size.

BEAMEUP · 11-11-2009, 08:57 AM

Still need more info to give you a proper answer. Is this for a service or a feeder? If you are putting it in a pipe I wouldn't use URD, I would go XHHW for all conductors. URD will be a pain to pull thru a pipe.

bharbwyr · 11-11-2009, 09:18 AM

This is a feeder from the metermain to the house. I know that the URD is stiffer than the XHHW, but it seems that perhaps, as it comes "pre-assembled", it will be less likely to form the kinks that may occur while wrangling four separate conductors.

480sparky · 11-11-2009, 09:22 AM

Order you four seperate conductors on reels and get a reel stand.

Podagrower · 11-11-2009, 09:25 AM

XHHW insulation does not get nicked up as easily as THHN/THWN insulation, but XHHW does not pull as easily.

The NEC sometimes shows what conductors will fit in a pipe, but that doesn't mean you can pull it. For a pull this long, I would be looking for a place or thing to attach a pulley overhead and use some mechanical advantage to pull (even pulling down by hand beats pulling up).

heel600 · 11-11-2009, 10:05 AM

Quote:

Originally Posted by bharbwyr

I'm gearing up to pull almost 500' of 250kcmil aluminum through pvc conduit. Other than the steel sweeps at both ends the path is pretty straight, dipping down in the middle and gently sweeping across the driveway to the house. Can anybody out there recommend, based on their experience, the minimum conduit diameter that should keep me out of trouble? I'm hoping to be able to do it with manpower alone, maybe 3 or 4 guys. Is that ridiculous?
The cable will be 250,250,3/0 URD,USE and a #2 XHHW EGC

I'd go with a 3" PVC.

It's bigger than you need, but the sweeps are bigger, allows for bigger conductors in the future, and the cost is very minimal.

You're nuts to think you can pull 500' by hand. Can you drag the 500' reel on the ground? Now add the 2 90s.

Buy a small tugger. It'll be the best $2500 you ever spent.

RIVETER · 11-11-2009, 10:59 AM

Quote:

Originally Posted by heel600

I'd go with a 3" PVC.

It's bigger than you need, but the sweeps are bigger, allows for bigger conductors in the future, and the cost is very minimal.

You're nuts to think you can pull 500' by hand. Can you drag the 500' reel on the ground? Now add the 2 90s.

Buy a small tugger. It'll be the best $2500 you ever spent.

Also get plenty of wire pulling compound. Don't forget RELIEF pull boxes.

sparks134 · 11-11-2009, 11:19 AM

Get plenty of sleep, dont forget to eat your wheatys and pull it by hand!!!

RIVETER · 11-11-2009, 11:24 AM

Quote:

Originally Posted by bharbwyr

I'm gearing up to pull almost 500' of 250kcmil aluminum through pvc conduit. Other than the steel sweeps at both ends the path is pretty straight, dipping down in the middle and gently sweeping across the driveway to the house. Can anybody out there recommend, based on their experience, the minimum conduit diameter that should keep me out of trouble? I'm hoping to be able to do it with manpower alone, maybe 3 or 4 guys. Is that ridiculous?
The cable will be 250,250,3/0 URD,USE and a #2 XHHW EGC

Would you feel it is necessary to BOND TO GROUND the steel sweeps. If so, how would you go about it?

sparks134 · 11-11-2009, 11:26 AM

Quote:

Originally Posted by RIVETER

Would you feel it is necessary to BOND TO GROUND the steel sweeps. If so, how would you go about it?

Hell No!!!

RIVETER · 11-11-2009, 11:36 AM

Quote:

Originally Posted by sparks134

Hell No!!!

Are you saying that it is not necessary, or are you saying that you just are not going to do it?

sparks134 · 11-11-2009, 11:38 AM

i dont think you need to, but not sure!

Old Spark · 11-11-2009, 11:42 AM

Well, I agree with the other suggestions about using XXHW on spools. You should be able to rent a puller or tugger if buying one is not feasible. Use lots of lube (do not use yellow lube, bad stuff) install the 2.5" or 3" conduit. Did you do a voltage drop calc.? Thats a long pull. Buy the way is it possible to install the meter closer to the house so the utility will make the long pull instead of you?
David Channell SSE

Old Spark · 11-11-2009, 11:43 AM

A ground rod.
David Channell SSE

Old Spark · 11-11-2009, 11:46 AM

In California, the steel sweeps do have to be bonded. In the transformer we have to use a ground rod, at the panel its easy.

480sparky · 11-11-2009, 11:48 AM

Quote:

Originally Posted by David Channell

In California, the steel sweeps do have to be bonded. In the transformer we have to use a ground rod, at the panel its easy.

So if I run PVC underground, and use steel sweeps to prevent the PVC ones from getting sawn along the insides from the rope, how do I bond them?

Old Spark · 11-11-2009, 11:56 AM

You need to install grounding bushings on the open ends of the steel sweeps. I they are not open because you have nipples or conduit continuing, the be sure to use steel nipples not pvc. When you finally terminate, then use the grounding (bonding) bushing. It is metal with a ground clamp attached. We have to use this on all underground metal conduits in Calif.
David Channell

sparks134 · 11-11-2009, 12:00 PM

i'm not following!!!???

480sparky · 11-11-2009, 12:01 PM

So instead of using 10,000 feet of PVC with steel sweeps for lights in a mall parking lot, I now have to pay for all steel raceways just to bond my sweeps?

I'll cite 250.86 Exc. 3 before I do that.